DE 33 15 835 C2 discloses a vacuum pressure casting device that uses a crucible with melt material. Via a site-mounted thermocouple, it is intended to detect temperature changes that are caused by the melt material, even if only small quantities of melt material are introduced.
It is true that this solution as presented aims at implementing a quick adaptation of the firing furnace temperature via a main controller and an auxiliary controller, protection against overtemperature also being built in. However, this solution is not suitable in principle if, apart from the quantity of material provided for melting, the temperature thereof is also different.
Furthermore, it is known per se from DE 196 06 493 C1 also to measure the temperature of the firing material in a dental firing furnace in the immediate vicinity of the firing material. It is provided in this solution to move the firing material in order to balance the desired temperature with the actual temperature along a temperature gradient. However, this brings about a corresponding vibration of the firing material that is not desired in some cases. In particular, this solution is also not suitable if use is made of a press furnace since the effect of the press ram that is built into the furnace hood is to fix the site at which the muffle must be located as carrier for the firing material.
Furthermore, it has already been proposed per se to evaluate the measured temperatures via a very complicated control device, and to adapt the firing temperature to the requirements. For example, there is a difference between the sintering temperatures for different ceramic materials from which dental restoration parts are produced, and the sinter firings must proceed with a temperature profile other than, for example, a glaze firing. It has also become known to display the firing curve graphically in order to provide the dental technician with better information.
Finally, it has also become known to use preheating furnaces that preheat the ceramic blanks to the temperature desired in each case, and this can differ depending on the ceramic. The prepared muffle can thus be set to the preheating temperature such that the temperature gradients in the actual press furnace are reduced during pressing. However, it is possible thereby not only for the muffle sizes themselves to differ, but different ceramics can also be used such that there is respectively a need for a very complicated adaptation in order to set the optimum temperature profile for the sinter firing. These different requirements can be met only inadequately with the furnaces known to date.